AP Statistics: 2012 Released Exam MC

Of the following dotplots, which represents the data that has the greatest standard deviation?

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A random sample of 374 United States pennies was collected, and the age of each penny was determined. According to the boxplot, what is the approximate interquartile range (IQR) of the ages?

• 8

• 10

• 16

• 40

• 50

The histogram shows the number of minutes needed by 45 students to finish playing a computer game. Which of the following statements is correct?

• The distribution is skewed to the right.

• The distribution is skewed to the left.

• The distribution appears to be normal.

• The distribution appears to be chi-square.

• THe distribution appears to be uniform.

A bank surveyed all of its 60 employees to determine the proportion who participate in volunteer activities. Which of the following statements is true?

• The bank should not use the data from this survey because this is an observational study.

• The bank can use the result of this survey to prove that working for the bank causes employees to participate in volunteer activities.

• The bank did not select a random sample of employees, so the survey will not provide the bank with useful information.

• The bank would have to use the survey data to construct a confidence interval in order to estimate the proportion of employees who participate in volunteer activities.

• The bank does not need to use an inference procedure to determine the proportion of employees who participate in volunteer activities because the survey was a census of all employees.

The histogram displays the frequencies of waiting times, in minutes, for 175 patients in a dentist's office.

Which of the following could be the median of the waiting times, in minutes?

• 2.50

• 7.25

• 12.25

• 15.00

• 17.50

Data were collected on the amount, in dollars, that individual customers spent on dinner in an Italian restaurant. The quartiles for these data are as follows: Q1 = $36.27, Q2 = $44.27, Q3 = $58.97.

Which of the following statements must be true for these customers?

• At least half of the customers spent less than or equal to $44.27 and at least half spent greater than or equal to $44.27.

• Seventy-five percent of the customers spent between $36.27 and $58.97.

• Twenty-five percent of the customers spent less than or equal to $58.97 and the remaining 75 percent spent greater than or equal to $58.97.

• The mean amount spent by customers is $44.27.

• A majority of customers spent $44.27.

The weight of adult male grizzly bears living in the wild in the continental United States is approximately normally distributed with a mean of 500 pounds and a standard deviation of 50 pounds. The weight of adult female grizzly bears is approximately normally distributed with a mean of 300 pounds and a standard deviation of 40 pounds. Approximately, what would be the weight of a female grizzly bear with the same standardized score (z-score) as a male grizzly bear with a weight of 530 pounds?

• 276 pounds

• 324 pounds

• 330 pounds

• 340 pounds

• 530 pounds

A company sells concrete in batches of 5 cubic yards. The probability distribution of X, the number of cubic yards sold in a single order for concrete from this company, is shown in the table.

The expected value of the probability distribution of X is 19.25 and the standard deviation is 5.76. There is a fixed cost to deliver the concrete. The profit Y, in dollars, for a particular order can be described by Y = 75X - 100. What is the standard deviation of Y?

• $332.00

• $432.00

• $532.00

• $1,343.75

• $1,400.00

Based on a survey of a random sample of 900 adults in the United States, a journalist reports that 60 percent of adults in the United States are in favor of increasing the minimum hourly wage. If the reported percent has a margin of error of 2.7 percentage points, which of the following is closest to the level of confidence?

• 80.0%

• 90.0%

• 95.0%

• 95.5%

• 99.0%

A compact disc (CD) manufacturer wanted to determine which of two different cover designs for a newly released CD will generate more sales. The manufacturer chose 70 stores to sell the CD. Thirty-five of these stores were randomly assigned to sell CDs with one of the cover designs and the other 35 were assigned to sell the CDs with the other cover design. The manufacturer recorded the number of CDs sold at each of the stores and found a significant difference between the mean number of CDs sold for the two cover designs. Which of the following gives the conclusion that should be made based on the results and provides the best explanation for the conclusion?

• It is not reasonable to conclude that the difference in sales was caused by the different cover designs because this was not an experiment.

• It is not reasonable to conclude that the difference in sales was caused by the different cover designs because there was no control group for comparison.

• It is not reasonable to conclude that the difference in sales was caused by the different cover designs because the 70 stores were not randomly chosen.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the cover designs were randomly assigned to stores.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the sample size was large.